Statement A is incorrect as the complex is yellow-green, not red.
Statement B is incorrect because the complex shows low solubility in water, especially at neutral pH.
Statement C is incorrect because Ni(II) in square planar geometry has all d-electrons paired (d^8 configuration), not unpaired electrons.
Statement D is correct regarding the N-Ni-N bond angle being approximately 90° in square planar geometry.
Statement E is correct as the complex contains two five-membered metallacycles (chelate rings) per dimethylglyoxime molecule.
The incorrect statements are B, C, and E.